Commentators have rushed to weigh in on the political and economic implications of the Brexit referendum. But the potential security effects are just as important. At risk are operational matters such as data and intelligence sharing. But also in question is something more fundamental: the relationships that allow security services to live and breathe. The United Kingdom, EU, and other partners will now have to redefine their security and intelligence relationships.

In a tragic example of foreshadowing, French Minister of the Interior Bernard Cazeneuve stated in remarks at the George Washington University earlier this month that the terrorist threat level had never been so high. Last week’s attacks in Brussels plainly reinforce the point while begging the question of how they were possible.

Spending more on cybersecurity is a start but it's certainly no panacea. President Obama's new spending plans should come with policy proposals and organizational initiatives that stand in the way of protecting US networks from malicious hackers.

Estonia packs a punch in the cyber domain. The country is a world leader in cyber-related innovation, and it has charted that course without compromising security. Estonia initially gained global attention as a cyber-target, seeking to overcome a series of organized attacks in 2007 widely attributed to Russian groups. Estonia emerged energetically from those attacks, going beyond devising a coherent and expansive cyber-strategy calibrated defensively, to being one of the most wired countries in the world.